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 *     following disclaimer. 
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 *     following disclaimer in the documentation and/or other 
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 * 
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using System.Collections.Generic;
using System.Threading;
using XenAPI;
using System.Linq;

namespace XenAdmin.Actions
{
    public class DestroyHostAction : AsyncAction
    {
        public DestroyHostAction(Pool pool, Host hostToDestroy)
            : base(pool.Connection, string.Format(Messages.DESTROY_HOST_ACTION_TITLE, hostToDestroy.Name))
        {
            this.Pool = pool;
            this.Host = hostToDestroy;
            this.Description = Messages.WAITING;
            SetRBACPermissions();
        }

        private void SetRBACPermissions()
        {
            AddCommonAPIMethodsToRoleCheck();
            ApiMethodsToRoleCheck.Add("host.destroy");
            ApiMethodsToRoleCheck.Add("sr.forget");
        }

        private bool IsSRDetached(SR sr)
        {
            if (sr == null)
                return true;

            // wait 2 minutes for all SR's PBDs to detach
            const int max = 2 * 60;
            int i = 0;

            while (i++ < max)
            {
                if (!sr.HasPBDs)
                    return true;

                Thread.Sleep(1000);
            }

            return !sr.HasPBDs;
        }

        protected override void Run()
        {
            Description = Messages.DESTROY_HOST_ACTION_DESC;
           
            List<SR> srList = Connection.Cache.SRs.Where(sr => Host.Equals(sr.GetStorageHost()) && sr.IsLocalSR).ToList();
            // number of SRs to forget + 1 host to destroy
            int n = srList.Count + 1;
            double p = 100.0 / n;
            int i = 1;

            RelatedTask = XenAPI.Host.async_destroy(Session, Host.opaque_ref);
            PollToCompletion(0, p);

            Description = Messages.DESTROY_HOST_ACTION_REMOVE_SRS_DESC;
            // remove SRs which belonged to destroyed Host
            foreach (SR sr in srList)
            {
                if (!IsSRDetached(sr))
                {
                    Description = Messages.DESTROY_HOST_ACTION_COMPLETED_SRS_NOT_REMOVED_DESC;
                    return;
                }

                int lo = (int)(i * p);
                int hi = (int)((i + 1) * p);
                RelatedTask = XenAPI.SR.async_forget(Session, sr.opaque_ref);
                PollToCompletion(lo, hi);
                i++;
            }
            Description = Messages.DESTROY_HOST_ACTION_COMPLETED_DESC;
        }
    }
}